Applied Mechanics and Materials Vols. 166-169

Abstract: Structure may encounter higher seismic fortification intensity than adopted. So how the structure reacts in that case becomes a concerned problem for civil engineers. In order to solve the problem, the response of a steel braced frame structure is analyzed in this paper when facing higher seismic fortification intensity. The result shows that the lateral sway between layers, the vertex displacement, the bending and shear strength of the frame beams and the stability of the components are still meet the design requirements, and steel frame structure has good seismic performance.

Abstract: The Rigid-Body-Spring-Model was applied for analyzing fire-damaged concrete beam with voronoi random mesh. Material models of fire-damaged concrete was defined by the experiment. To evaluate the performance and effectiveness of the RBSM with voronoi random mesh, four models of fire damaged concrete beam at various temperatures covered 20°C and 100 to 800°C were analyzed. According to the results, heated specimen 800°C has the lowest strength capacity and internal stress comparing to the other specimens. Main crack of 800°C specimen appears earlier than other specimens. Strength capacity of heated specimen 400°C was higher than the results of unheated specimen because of hydration reaction of large cement clinker was accelerate during heating.

Abstract: The corrosion fatigue character of aluminum alloy material was investigated. The aluminum alloy specimens were pre-corroded in different corrosive solutions and then were tested under fatigue load. The two key parameters of describing corrosion damage, surface corrosion damage ratio and average depth of corrosion damage, were analyzed using experimental observation and finite element method. The preliminary results indicated that the two key parameters could be the appraisal parameters for corrosion damage of aluminum alloy structure.

Abstract: This research involves developing a project management system for the piping construction projects. Piping construction as a part of mechanical package usually takes over 30% of total efforts for the industrial construction projects, thus is typically recognized as a critical work scope for the similar kinds of construction projects. Therefore, the piping construction under budget and within schedule is one of the crucial tasks for management, and it takes accurate prediction of performance throughout the project execution process. The researchers suggest an alternative model be utilized to accurately forecast piping work efforts required for the piping construction. The model developed incorporates difficulty factors to estimate the level of efforts more accurately and the validation of the model is in progress. The alternative method of forecast may improve the accuracy significantly.

Abstract: The research and application condition of top ring beam for the foundation pit engineering is introduced. A 3D finite element model of row piles and top ring beam is calculated and several major parameters of the beams are discussed. On the basic of the FEM results, a simplified method is proposed to calculate the equivalent stiffness of the beam in a typical design profile for practical engineering.

Abstract: Gravity anchor is one of essential forced components of steady suspension bridge. The paper takes the example of the finite element numerical simulation of steady suspension bridge gravity anchor, main contents include: First, performance parameters of concrete and hydration heat of cement is collected, the one-fourth block of anchor model is established by large-scale general finite element software ANSYS. The process of establishing finite element analysis model includes the input of the model parameters, the boundary conditions set of finite element model, and the mesh of finite element analysis model. Then, the numerical simulation computation to temperature field of gravity anchor is carried by finite element software ANSYS. Finally, from the temperature field distribution curves, studying the temperature distribution rule of concrete pouring and drawing some conclusions.

Abstract: The piezoelectric ceramic (PZT) smart aggregates as sensor and actuator were embedded into large eccentric compression column to generate sin-sweep signals on-line and detect real-time signals before and after damage. The PZT active health monitoring and wavelet packets energy method were focused experimentally on the effectiveness validation of damage detection. The index of root mean square deviation is used to evaluate the damage information by compare of the energy change of damage signals. A statistical pattern identification algorithm is proposed by wavelet packets decomposition and statistical characteristics analysis of damage signal amplitude. The results show that the amplitude of active monitoring signals produces a larger attenuation. The sweep wave signal as active health monitoring is an effective method to identify damage degree and general location of concrete structure. The developed method can primarily be used in the damage evaluation.

Abstract: The hysteretic behaviors of concrete filled steel tube columns under low cyclic loads were analyzed for verification the accumulated energy dissipation performance. The accumulated ductility coefficient influencing factors, such as slenderness ratio, axial compression ratio and sectional steel ratio, were analyzed. It is indicated that these columns have a better energy dissipation capacity. The energy dissipation capacity decreases with the axial compression ratio increasing, but the influence of slenderness ratio and steel ratio to accumulated ductility coefficient is not clear, this is because the influence of difference loading system.

Abstract: In this paper, the ultimate behaviour of bolted connections and the effect of various configurations of bolted connections on the ultimate strength are thoroughly investigated. Through finite element modelling, the stress distributions, bolt load distributions, and the effect of bolt sizes and bolt arrangements are studied in detail. The finite element analysis results show that the square shape arrangement of a bolted connection has a higher ultimate strength than that of the diamond shape arrangement. The ultimate strength of bolted connection increases as the bolts size increase until a limitation of improvement in strength is reached.

Abstract: For a space simply supported truss bridge model, a method named element modal strain energy (MSE) was firstly adopted in the field of the optimal sensors placement. By taking nodes MSE, nodes distance matrix reciprocal as weights, and combining with optimal matching in graph theory, how to apply the method for optimal sensors placement was stated. Through analyzing on the random vibration property of the bridge finite element model, the nodes position of larger acceleration response was compared with the optimal placement got from the above method, which could verified the effectiveness of optimal sensors placement.